A third-order accurate, upwind-biased, thin-layer
Navier-Stokes zonal code (STAGE-2) has been used to investigate stator
clocking in a multistage compressor. The effects of stator clocking on
the unsteady flow within a low-speed þstage compressor have been
investigated. The results indicate that clocking in multistage
compressors is a complex, non-linear phenomenon which warrants further
study. In particular,

Variations in efficiency, force amplitudes and frequencies
are functions of the relative position of the clocked airfoil
and convected wake groupings.

The optimal combination of high efficiency and low force amplitude
occured when the stator-1 wake convected along the pressure
surface of stator-2.

A slight movement of the stator-1 wake to the suction surface of
stator-2 resulted in a distinct loss in efficiency
and higher amplitude unsteadiness.

When performing parametric studies of airfoil
clocking, one must be careful in choosing the parameter
variation in order not to overlook these effects.